King Robert III of Scotland had attempted to send his younger son James Stewart to France to guard him from the machinations of his uncle, Robert, Duke of Albany, but the twelve year old James was captured by English ships just off Flamborough Head. When King Robert died soon after on 4th April,
1406 James succeeded to the Scottish throne as James I. While the young King grew to manhood in English captivity, his ambitious and self-serving uncle was appointed Regent and Governor of Scotland in his absence and exhibited no haste in securing his nephew's release.

James received an education and traveled with the English court, where he learned much about government and administration, which helater put intopractice when he returned to his native Scotland. Joan met James I during his English captivity, the couple had known each other from at least 1420. James fell in love with Joan, she is said to have been the inspiration for his famous long poem, The Kingis Quair, written after he saw her from his window in the garden. James negotiated a release from captivity the previous year, the English favoured his alliance with the Beauforts which it was hoped would continue Scotland's alliance with the England, rather than their traditional ally France.
Joan's dowry of 10,000 merks was subtracted from the substantial ransom of 60,000merks the Scots had to pay for the return of their king. James and Joan were married on 12 February 1424 at St Mary Overie Church in Southwark. The newly weds attended festivities at Winchester Palace hosted by Joan's uncle, the powerful Cardinal Henry Beaufort. They then started their journey north to Scotland.

Joan was crowned queen of Scotland on 2 or 21, May at Scone Abbey by Henry de Wardlaw, Bishop of Saint Andrews. James, unlike his father, possessed a strong and resolute character, and was determined to crush the threat posed by the power of the Albany Stewarts and promptly confiscated their estates. Murdoch Stewart and his two sons were executed on Castle Hill, at Stirling. In 1429, Alexander Macdonald, Lord of the Isles, was captured after burning and pillaging in the Scottish Highlands. Dressed as a penitent, he was compelled to appear before the high altar in Holyrood Abbey. In a pre-staged scene, Joan pleaded with her husband for his life. This allowed James to save face while exercising mercy.

The couple produced eight children, seven of whom survived to adulthood:-

James I was murdered by assassins led by Sir Robert Graham in Perth on 21 February 1437, Joan was also wounded in her frantic attempts to protect her husband. Joan successfully directed her husband's supporters to attack his assassin Walter Stewart, Earl of Atholl, but was forced to give up the regency to The Earl of Douglas three months later, though she remained in charge of the new king her son James II.

Near the end of July 1439, Joan married James Stewart, the Black Knight of Lorne, the son of Sir John Stewart (d. 26 Apr 1421), an ambassador to England and a direct male line descendant of Alexander Stewart, 4th High Steward of Scotland. The couple had three sons:-

James Stewart was an ally of the Black Douglases, Earls of Douglas, and plotted with him to overthrow Alexander Livingston, governor of Stirling Castle. Livingston had Joan arrested in August 1439 and forced her to relinquish custody of the young king. He imprisoning her in Stirling Castle, while Sir James Stewart and his brother Sir William were incarcerated in the castle's dungeon. They were later released on good behaviour. The conflict however continued and and Joan was besieged at Dunbar Castle, where she died on 15 July 1445. She was buried beside her first husband James I, in the Carthusian Priory at Perth.